本文選題：沖蝕磨損　切入點(diǎn)：混凝土　出處：《蘭州交通大學(xué)》2016年博士論文

【摘要】：已經(jīng)開(kāi)通的蘭新高速鐵路沿線穿越五大強(qiáng)風(fēng)區(qū),風(fēng)區(qū)地段風(fēng)力強(qiáng)勁、風(fēng)期長(zhǎng),強(qiáng)風(fēng)攜帶的沙粒對(duì)風(fēng)區(qū)地段的混凝土橋梁的梁體、墩身和鐵路路基產(chǎn)生了嚴(yán)重的沖蝕磨損,造成如橋梁墩身表面的水泥剝落以及水泥與骨料之間微裂紋的產(chǎn)生,這些損傷可能進(jìn)一步加劇混凝土結(jié)構(gòu)的其他病害和損傷,大大降低混凝土結(jié)構(gòu)的耐久性。混凝土結(jié)構(gòu)耐久性的降低不僅影響其設(shè)計(jì)壽命,同時(shí)造成龐大的維修費(fèi)用,也給列車(chē)的行車(chē)安全造成了重大的隱患。關(guān)于混凝土結(jié)構(gòu)材料的沖蝕磨損,目前人們重點(diǎn)研究含沙水流對(duì)水工混凝土結(jié)構(gòu)材料的沖蝕磨損,主要研究了試驗(yàn)方法、沖蝕磨損機(jī)理、評(píng)價(jià)指標(biāo)和抗磨措施,并取得了一些進(jìn)展。而對(duì)于風(fēng)沙環(huán)境(氣固兩相流)下,混凝土結(jié)構(gòu)材料沖蝕磨損的試驗(yàn)方法、沖蝕磨損機(jī)理和防護(hù)、修補(bǔ)材料的研究還鮮見(jiàn)報(bào)道。為此,本文采用氣流挾沙噴射法,模擬戈壁風(fēng)沙環(huán)境,對(duì)混凝土、改性環(huán)氧樹(shù)脂、環(huán)氧樹(shù)脂基復(fù)合材料及水泥基防護(hù)、修補(bǔ)砂漿進(jìn)行沖蝕磨損試驗(yàn),分析其沖蝕磨損行為和沖蝕磨損機(jī)理。結(jié)合現(xiàn)場(chǎng)試驗(yàn)和室內(nèi)試驗(yàn)探討了改性環(huán)氧樹(shù)脂基復(fù)合材料作為強(qiáng)風(fēng)沙流地區(qū)混凝土結(jié)構(gòu)沖蝕磨損防護(hù)材料的可行性。主要研究?jī)?nèi)容和結(jié)論如下:(1)依據(jù)ASTMC418-2005《混凝土沖蝕磨損標(biāo)準(zhǔn)試驗(yàn)方法》研發(fā)了沖蝕磨損試驗(yàn)機(jī),該試驗(yàn)機(jī)由供氣系統(tǒng)、供沙系統(tǒng)、噴槍和噴嘴系統(tǒng)及試樣室等4個(gè)部分構(gòu)成;分析了現(xiàn)場(chǎng)收集沙的粒徑分布,確定了室內(nèi)試驗(yàn)沙的粒徑范圍;校核了氣流速度和壓力的關(guān)系,以便確定試驗(yàn)速度。(2)研究了沖蝕速度、沖蝕角度、沖蝕時(shí)間和沙流量等參數(shù)對(duì)混凝土試樣沖蝕磨損的影響,試驗(yàn)發(fā)現(xiàn)各試樣的沖蝕率和風(fēng)沙流速度滿(mǎn)足冪指數(shù)關(guān)系,擬合速度指數(shù)在2.0-3.2之間,符合脆性材料的沖蝕磨損規(guī)律;各試樣在90°沖蝕時(shí)沖蝕率高,而在45°沖蝕時(shí)沖蝕率低,與脆性材料的沖蝕規(guī)律相一致;混凝土試樣的沖蝕率隨沙流量的增大先降低后增大;混凝土材料的沖蝕磨損機(jī)制為:表面層水泥石的開(kāi)裂脫落和次表面層的選擇性磨損。(3)采用瀝青、納米SiO2和改性脂肪胺固化劑對(duì)雙酚A型環(huán)氧樹(shù)脂進(jìn)行增韌改性,研究了其耐久性和抗沖蝕磨損性能。試驗(yàn)發(fā)現(xiàn)瀝青、納米SiO2和改性脂肪胺固化劑提高了環(huán)氧樹(shù)脂的力學(xué)性能、耐久性和沖蝕磨損性能,其沖蝕時(shí)表現(xiàn)出半塑性材料的沖蝕特征,最大沖蝕率出現(xiàn)在45°沖蝕角,且沖蝕抗力相比于混凝土有了極大的提高;改性環(huán)氧樹(shù)脂的沖蝕是沖蝕能量法向分量和切向分量共同作用的結(jié)果,法向分量使材料表面產(chǎn)生裂紋和破碎,切向分量使材料表面產(chǎn)生切削。(4)制備了玻璃(碳)纖維增強(qiáng)環(huán)氧樹(shù)脂復(fù)合材料,研究了含膠量、纖維取向、纖維布類(lèi)型和沖蝕參數(shù)等對(duì)復(fù)合材料沖蝕磨損性能的影響。試驗(yàn)發(fā)現(xiàn)環(huán)氧樹(shù)脂基復(fù)合材料的沖蝕行為表現(xiàn)出半塑性材料的沖蝕特征,最大沖蝕率出現(xiàn)在45°~60°;對(duì)于單向纖維增強(qiáng)環(huán)氧樹(shù)脂復(fù)合材料,在沖蝕角為45°時(shí),其沖蝕率與沖蝕速度呈指數(shù)關(guān)系,速度指數(shù)為2.1-2.8;在相同的沖蝕條件下,單向纖維增強(qiáng)環(huán)氧樹(shù)脂復(fù)合材料垂直沖蝕的沖蝕率比平行沖蝕的高,含膠量越高復(fù)合材料的沖蝕抗力就越高;復(fù)合材料的主要沖蝕磨損機(jī)制為微裂紋的產(chǎn)生、纖維的彎曲斷裂、纖維與基體剝離以及基體的顯微切削。(5)制備了不同的水泥基防護(hù)、修補(bǔ)砂漿,研究了砂漿強(qiáng)度等級(jí)、砂子級(jí)配、丙乳含量、纖維類(lèi)型和含量對(duì)水泥基防護(hù)、修補(bǔ)砂漿沖蝕磨損性能的影響。試驗(yàn)發(fā)現(xiàn)水泥石和水泥基防護(hù)、修補(bǔ)砂漿的沖蝕率均隨著風(fēng)沙流速度的增大而增加;PP和PVA纖維增強(qiáng)砂漿的沖蝕率隨沖蝕角度的增加呈鋸齒狀變化,其余砂漿的沖蝕規(guī)律與脆性材料相一致;砂漿的強(qiáng)度等級(jí)越高,其沖蝕抗力也越高;砂子級(jí)配越大,砂漿的沖蝕抗力越高;達(dá)到一定摻量的丙乳能在砂漿中形成聚合物膜特殊結(jié)構(gòu),提高砂漿的韌性和沖蝕抗力;適宜量的PP和PVA纖維能對(duì)砂漿起到增強(qiáng)和增韌作用,從而能夠提高砂漿的沖蝕抗力,特別是高角度沖蝕時(shí)的沖蝕抗力。
[Abstract]:Lanzhou Xinjiang has been opened along the high-speed railway passing through five strong wind area, wind area of strong wind, wind period, strong wind carried sand concrete girder bridge on the wind section of the pier and railway roadbed caused serious erosion, such as caused by micro cracks between the cement surface and spalling of bridge pier cement and aggregate, these injuries may further exacerbate other diseases and damage of the concrete structure, greatly reduce the durability of the concrete structure. To reduce the durability of concrete structure not only influences the design life, and caused huge maintenance costs, but also to the running safety of train caused significant risks. On the erosion wear of concrete structure material. At present, people focus on sediment erosion of material of hydraulic concrete structure wear, mainly studied the test method, the erosion mechanism, evaluation index and Anti-wear measures, and made some progress. But for the sand environment (gas-solid two-phase flow), test method of erosion wear of concrete structure material, erosion mechanism and protection of repair materials is rarely reported. Therefore, the sediment air injection method, simulation of Gobi sandy environment, concrete, change epoxy resin, epoxy resin composite materials and cement mortar protection, erosive wear test, analysis of the erosion wear behavior and erosion wear mechanism. Combined with the field test and laboratory test of modified epoxy resin based composite material as the wind sand flow erosion area of concrete structure wear protection material feasibility is discussed. The main research contents and the conclusions are as follows: (1) on the basis of ASTMC418-2005< concrete erosion wear test method standard > developed erosion test machine, the test machine comprises a gas supply system for sand spraying system The 4 part of the gun and nozzle system and sample room; analyzes the collected sediment particle size distribution, the indoor test sediment particle size range; the relationship between flow velocity and pressure check, in order to determine the test speed. (2) studied the impact velocity, impact angle, erosion time and sand flow parameters on the influence of concrete specimen erosion test, found that the sample erosion rate and sand flow velocity exponential fitting, velocity index between 2.0-3.2, with the erosion of brittle material of each specimen in 90 DEG; erosion erosion rate is high, and in the 45 degree erosion erosion rate is low, consistent with erosion behavior of brittle materials; erosion of concrete specimens increases with the flow rate of sand decreased first and then increased; the concrete material erosion wear mechanism is that wear cracking surface layer of cement stone falling and secondary surface layer (3) used. Asphalt, nano SiO2 and modified aliphatic amine curing agent for toughening modification of bisphenol A type epoxy resin, study its durability and anti erosion performance. Experiment results showed that asphalt, nano SiO2 and modified aliphatic amine curing agent to improve the mechanical properties of epoxy resin, durability and erosion resistance, the erosion show the erosion characteristics of semi plastic material, the maximum erosion rate in the 45 degree angle erosion and erosion resistance, compared to the concrete has been greatly improved; the erosion of modified epoxy resin as a result of the erosion energy method to the component and tangential component interaction, the normal component of the surface crack and breakage the tangential component of the material, surface cutting. (4) (c) were prepared by glass fiber reinforced epoxy resin composite material of rubber content, fiber orientation, fiber type and erosion parameters on the composite erosion wear resistance. Ring. Experiment results showed that the erosion behavior of epoxy resin composites exhibit erosion characteristics of semi plastic material, the maximum erosion rate appeared at 45 DEG ~60 DEG; for unidirectional fiber reinforced epoxy resin composite material, the erosion angle is 45 degrees, the erosion rate and erosion rate exponentially, the speed index was 2.1-2.8; in the same conditions of erosion, erosion of unidirectional fiber reinforced epoxy resin composite vertical erosion rate than parallel erosion, erosion resistance of rubber content higher composite material is higher; the main composite material erosion wear mechanism is micro cracks, bending fracture of fiber, fiber and matrix stripping and matrix micro cutting. (5) preparation of cement based protection, different mortar strength grade of mortar, sand gradation, emulsion content, protective fiber type and content on the cement mortar, repair erosion performance Effect of cement and cement. Experiment results showed that base protection, erosion repair mortar rate increases with the increasing of sand flow rate; PP and PVA fiber reinforced serrated change increase of mortar erosion rate with the erosion angle, consistent with the erosion law of mortar brittle materials; mortar strength grade is higher, the erosion resistance is also higher; the greater the sand gradation, erosion resistance of mortar is higher; reach a certain dosage of acrylic emulsion can form special polymer film structure in mortar, improve the mortar toughness and erosion resistance; appropriate amounts of PP and PVA fiber to enhance and improve the toughness of the mortar, which can improve the erosion the resistance of mortar, especially the erosion resistance of high angle erosion.

【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：TV431

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